<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            background-color: grey;
        }
        .container {
            margin: 100px auto;
            width: 300px;
        }

        h3 {
            margin-bottom: 20px;
            margin-left: 100px;
        }
        .two {
            margin-left: 16px;
        }
        .three {
            margin-left: 100px;
        }
    </style>
</head>
<body>
    <div class="container">
        <form action="http://www.baidu.com">
            <h3>用户注册</h3>
            <p>用户名<input type="text" value="" name="a" placeholder="请输入用户名"></p> 
            <p class="two">密码<input type="password" value="" name="b" placeholder="请输入密码"></p> 
            <input type="submit" value="注册" class="three">
        </form>
    </div>
    
</body>
</html>